Can lime be used to raise pH?

[edweather]

I know this question is probably "out there," but I also garden and have quite a bit of agricultural lime lying around. Just wondering if it could be used as a pH raiser? Feedback appreciated (after you stop laughing.)

 

[NWMNMom]

Are you kidding? We use that for industrial purposes at work, it's caustic and we recently had an employee who spent a week in the hospital after lime and water sprayed his face. I know MA is also dangerous but I'm thinking absolutely not - water does not neutralize that stuff. I can't think of a good reason to use it when MA is so cheap.

 

[JohnT]

Are you kidding? We use that for industrial purposes at work, it's caustic and we recently had an employee who spent a week in the hospital after lime and water sprayed his face. I know MA is also dangerous but I'm thinking absolutely not - water does not neutralize that stuff. I can't think of a good reason to use it when MA is so cheap.

Agricultural lime is just crushed limestone. Very safe for people, but it wouldn't be appropriate for raising the pool pH because it has so much calcium and is so slow to dissolve.

 

[chem geek]

Are you kidding? We use that for industrial purposes at work, it's caustic and we recently had an employee who spent a week in the hospital after lime and water sprayed his face.

I believe you are thinking of lye aka caustic soda or sodium hydroxide, not lime which is calcium carbonate. Lye is in some ways nastier than Muriatic Acid as it can cause chemical burns more quickly but both are very bad for the eyes and can cause blindness.

I agree with John that lime dissolves too slowly to be of practical use and it increases Calcium Hardness as well. 13.35 ounces weight of lime in 10,000 gallons raises the CH by 10 ppm and is equivalent to 14.8 ounces of calcium chloride plus 14.1 ounces of sodium carbonate (pH Up, washing soda) except the latter also increases sodium chloride salt.

 

[edweather]

Thanks for the replies. Yes, I was not talking about lye, or even hydrated lime, just crushed dolomite limestone. Since I have a vinyl liner in my pool, and calcium hardness isn't really an issue, is there any harm in trying a "little" to see how it does?

 

[JasonLion]

Calcium can be very very low without problems in a vinyl liner pool, but high calcium levels are a problem for any kind of pool.

 

[chem geek]

is there any harm in trying a "little" to see how it does?

There is no harm in you using a little to see what it does. Just note the effects that I gave to you. You can at least see if it will end up dissolving at all -- I think that will be the biggest problem with it. As I wrote, it's really the same as adding sodium carbonate and calcium chloride except it doesn't add extra sodium chloride salt, but it is likely very slow to dissolve.

 

[edweather]

Thanks again for responding. I just had to ask, seeing as I bought a 40lb bag of lime this year, which will probably last me 10 years. If I do try some, it won't be until I check current the CH. Thanks again.

 

[CUTiger78]

Did you try adding the lime? How well did it work?

 

[NWMNMom]

Are you kidding? We use that for industrial purposes at work, it's caustic and we recently had an employee who spent a week in the hospital after lime and water sprayed his face.

I believe you are thinking of lye aka caustic soda or sodium hydroxide, not lime which is calcium carbonate. Lye is in some ways nastier than Muriatic Acid as it can cause chemical burns more quickly but both are very bad for the eyes and can cause blindness.

I agree with John that lime dissolves too slowly to be of practical use and it increases Calcium Hardness as well. 13.35 ounces weight of lime in 10,000 gallons raises the CH by 10 ppm and is equivalent to 14.8 ounces of calcium chloride plus 14.1 ounces of sodium carbonate (pH Up, washing soda) except the latter also increases sodium chloride salt.

BTW, not talking about lye, talking about the millions of pounds of lime rock we use in the sugar mfg process - we have lime kilns to make milk of lime to help precipitate out the impurities while boiling - the lime dust from the rock has resulted in MANY employees with burns when the dust comes into contact with their sweat or any moist skin

 

[JamesW]

BTW, not talking about lye, talking about the millions of pounds of lime rock we use in the sugar mfg process - we have lime kilns to make milk of lime to help precipitate out the impurities while boiling - the lime dust from the rock has resulted in MANY employees with burns when the dust comes into contact with their sweat or any moist skin

Agricultural lime is mostly calcium carbonate, which is not particularly dangerous. For example, Tums (the antacid) is made of calcium carbonate. Milk of lime is calcium hydroxide, which is caustic in the same way that lye (sodium hydroxide) is.

For your process, calcium carbonate from mined rocks is heated in kilns to form calcium oxide (aka quicklime or burnt lime), which is then hydrated to form calcium hydroxide. During hydration, heat is given off. The burns you are reporting sound like they are due to exposure to calcium oxide. I don't think that the lime dust (calcium carbonate) from the rock would have any serious adverse effect on anyone exposed.

Agricultural lime can contain some calcium hydroxide, calcium oxide and/or magnesium oxide, which are caustic. Therefore, it would depend on the chemical composition of the lime. If the lime contained significant levels of calcium hydroxide, calcium oxide and/or magnesium oxide, then it would be more dangerous to use.

As far as using calcium carbonate for raising pH or calcium, I would advise against it as it could increase the risk of scaling due to locally high levels of calcium and carbonate.

 

[teapot]

Are you kidding? We use that for industrial purposes at work, it's caustic and we recently had an employee who spent a week in the hospital after lime and water sprayed his face. I know MA is also dangerous but I'm thinking absolutely not - water does not neutralize that stuff. I can't think of a good reason to use it when MA is so cheap.

Just remember you don't raise PH with MA.

 

[NWMNMom]

I was only stating that MA is a dangerous chemical we introduce directly into our pools : )

 

[Pool-creetin]

I use pickling lime to increase alk and calcium in my reef tank. Great stuff, but as noted above it will raise your CA and ALK too besides ph.

 

[RickstersPool]

Lime to reduce hardness - was Re: Can lime be used to raise

What about using pickling lime to reduce hardness?

I found several references that say it makes calcium precipitate out?

http://www.tutorvista.com/content/chemi ... -water.php

 

[chem geek]

Welcome to TFP!

Pickling lime (aka slaked lime) is calcium hydroxide. Adding a substance that has calcium in it to try and reduce calcium isn't as good as simply adding a pure base such as lye (sodium hydroxide) that raises the pH to precipitate calcium carbonate without adding either calcium nor carbonates itself. The main risk to raising the pH to lower calcium (and carbonate) is that the high pH can also create metal stains and can have scale form. One doesn't have a lot of control over where the calcium carbonate (scale) is formed, especially in a plaster pool. If one is more concerned with lowering calcium and doesn't already have the water saturated with calcium carbonate, then one can use washing soda (pH Up; sodium carbonate) and then deal with lowering the higher TA later using acid and aeration.

It is probably easier to lower calcium by adding sodium oxalate to form calcium oxalate that may precipitate without forming scale on plaster. Any excess oxalate is then readily removed by oxidation with chlorine that produces carbon dioxide. Note that using sodium oxalate will remove any chlorine in the pool since it is a reducing agent (similar to using ascorbic acid). However, this process has not been done enough on this forum to recommend it.

 

[RickstersPool]

Wow Chem Geek! a fountain of knowledge and response in 10 minutes!

I found Solarboy's adventures with Oxalic Acid (oxalic-acid-treatment-and-calcium-oxalate-worries-t32659.html?hilit=oxalate), but he didn't mention if it lowered his CH and it seems he had trouble filtering out the precipitate and raised the CL enough to put everything back into solution.

My CH is around 600 and I'm tired of the deposites on my natural quartzite and grout.
I'm looking for a way to reduce the CH.

I live in Southern California so no rain to thin out the water. It just gets thicker.
Our town water is rather high (I don't know the number), so draining wouldn't help that much (the pool/water is only two years old and the deposites started right away).

I see references to Caltreat and Cal-Sok, but they are sketchy. Ditto for Calgon.

The oxalic acid sounds very intriguing, it looks like there was lots of calcium on the floor, how much would it lower CH?
I have a cartridge filter and can't vacuum to waste, but I'd figure something out.

Any ideas would be appreciated.

 

[JamesW]

Reverse osmosis is available in some part of southern California.